-LRB- CNN -RRB- -- Linguists announced Monday they have identified an endangered language known as Koro that is spoken by about 800 people in northeast India .

The language was unknown to science and recently came to light during an expedition by linguists traveling in India on fellowships for National Geographic , the linguists said in telephone interviews .

Koro belongs to the Tibeto-Burman language family , which is composed of a group of about 400 languages spoken primarily in east , central , south and southeast Asia and includes Tibetan and Burmese , according to linguist K. David Harrison .

Some 150 Tibeto-Burman languages are spoken in India alone , but no other language has been identified as closely related , said Harrison , an associate professor of linguistics at Swarthmore College in Swarthmore , Pennsylvania .

Like most languages , Koro is unwritten and transmitted orally . It is neither a dialect nor a sister language close to Hruso-Aka , despite being considered such by both Hruso and Koro people .

Koro shares some vocabulary with other languages spoken in the region but shares more features with languages spoken farther east , such as Milang and Tani , the linguists said in a news release issued by National Geographic .

Harrison and another National Geographic Fellow , Greg Anderson , led the expedition , called Enduring Voices , which brought Koro to light . Enduring Voices documents vanishing languages and cultures and assists with language revitalization .

Harrison and Anderson , director of the Living Tongues Institute for Endangered Languages , in Salem , Oregon , focused on Arunachal Pradesh , a remote area of northeast India that is considered the black hole of the linguistic world .

It is a language hotspot where there is room to study rich , diverse languages , many unwritten or documented . A permit is required to visit , few linguists have worked there and a reliable list of languages has never been drawn up .

`` On a scientist 's tally sheet , Koro adds just one entry to the list of 6,909 languages worldwide . But Koro 's contribution is much greater than that tiny fraction would suggest , '' Harrison writes in his book , `` The Last Speakers . ''

`` Koro brings an entirely different perspective , history , mythology , technology and grammar to what was known before . ''

In the news release , the linguists described their discovery as bittersweet : Of the approximately 800 people who speak Koro , few are under the age of 20 , meaning the language is endangered .

`` We were finding something that was making its exit , was on its way out , '' Anderson said . `` And if we had waited 10 years to make the trip , we might not have come across close to the number of speakers we found . ''

The team set out in 2008 in Arunachal Pradesh to document Aka and Miji , languages spoken in a small district there . The expedition went door to door among homes propped up on stilts to reach potential speakers of those little-known languages .

While recording the vocabularies , they detected a third language -- Koro . It was not listed in Indian language surveys , Indian censuses or standard international registries .

`` We did n't have to get far on our word list to realize it was extremely different in every possible way , '' Harrison said .

The inventory of sounds and the way these sounds were combined to form words were distinct from other languages spoken in the region .

An Aka speaker would call a pig `` vo '' and a Koro speaker would call a pig `` lele . ''

`` Koro could hardly sound more different from Aka , '' Harrison writes . `` They sound as different as , say , English and Japanese . ''

Anderson and Harrison said Aka is the traditional language of the region 's historic slave traders , and they hypothesized that Koro may have sprung from the slaves ; though they said more study is needed to determine the origin .

The project reports that a language becomes extinct every two weeks . By 2100 , it is estimated that more than half of the 6,910 languages spoken on earth will vanish . The team will return to India to continue studying Koro in November .

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Koro is spoken by only about 800 people , few of them under the age of 20

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Linguists traveling in northeast India came upon the language

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Koro was not listed in any Indian language surveys or other sources

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Koro 's sounds distinctly different from other tongues spoken in region